Allow layout_of_local to also use cached layouts

Author: oli-obk

src/librustc_mir/interpret/eval_context.rs

@@ -317,13 +317,16 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
     pub fn layout_of_local(
         &self,
         frame: &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>,
-        local: mir::Local
+        local: mir::Local,
+        layout: Option<TyLayout<'tcx>>,
     ) -> EvalResult<'tcx, TyLayout<'tcx>> {
         let cell = &frame.locals[local].layout;
         if cell.get().is_none() {
+            let layout = ::interpret::operand::from_known_layout(layout, || {
             let local_ty = frame.mir.local_decls[local].ty;
             let local_ty = self.monomorphize_with_substs(local_ty, frame.instance.substs);
-            let layout = self.layout_of(local_ty)?;
+                self.layout_of(local_ty)
+            })?;
             cell.set(Some(layout));
         }
 
@@ -507,7 +510,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
                 match local.state {
                     LocalState::Live(_) => {
                         // This needs to be peoperly initialized.
-                        let layout = self.layout_of_local(self.frame(), idx)?;
+                        let layout = self.layout_of_local(self.frame(), idx, None)?;
                         local.state = LocalState::Live(self.uninit_operand(layout)?);
                     }
                     LocalState::Dead => {
@@ -601,7 +604,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         assert!(local != mir::RETURN_PLACE, "Cannot make return place live");
         trace!("{:?} is now live", local);
 
-        let layout = self.layout_of_local(self.frame(), local)?;
+        let layout = self.layout_of_local(self.frame(), local, None)?;
         let init = LocalState::Live(self.uninit_operand(layout)?);
         // StorageLive *always* kills the value that's currently stored
         Ok(mem::replace(&mut self.frame_mut().locals[local].state, init))

src/librustc_mir/interpret/operand.rs

@@ -227,7 +227,7 @@ impl<'tcx, Tag> OpTy<'tcx, Tag>
 // Use the existing layout if given (but sanity check in debug mode),
 // or compute the layout.
 #[inline(always)]
-fn from_known_layout<'tcx>(
+pub(super) fn from_known_layout<'tcx>(
     layout: Option<TyLayout<'tcx>>,
     compute: impl FnOnce() -> EvalResult<'tcx, TyLayout<'tcx>>
 ) -> EvalResult<'tcx, TyLayout<'tcx>> {
@@ -461,10 +461,11 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         &self,
         frame: &super::Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>,
         local: mir::Local,
+        layout: Option<TyLayout<'tcx>>,
     ) -> EvalResult<'tcx, OpTy<'tcx, M::PointerTag>> {
         assert_ne!(local, mir::RETURN_PLACE);
         let op = *frame.locals[local].access()?;
-        let layout = self.layout_of_local(frame, local)?;
+        let layout = self.layout_of_local(frame, local, layout)?;
         Ok(OpTy { op, layout })
     }
 
@@ -473,14 +474,15 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
     fn eval_place_to_op(
         &self,
         mir_place: &mir::Place<'tcx>,
+        layout: Option<TyLayout<'tcx>>,
     ) -> EvalResult<'tcx, OpTy<'tcx, M::PointerTag>> {
         use rustc::mir::Place::*;
         let op = match *mir_place {
             Local(mir::RETURN_PLACE) => return err!(ReadFromReturnPointer),
-            Local(local) => self.access_local(self.frame(), local)?,
+            Local(local) => self.access_local(self.frame(), local, layout)?,
 
             Projection(ref proj) => {
-                let op = self.eval_place_to_op(&proj.base)?;
+                let op = self.eval_place_to_op(&proj.base, None)?;
                 self.operand_projection(op, &proj.elem)?
             }
 
@@ -504,7 +506,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             // FIXME: do some more logic on `move` to invalidate the old location
             Copy(ref place) |
             Move(ref place) =>
-                self.eval_place_to_op(place)?,
+                self.eval_place_to_op(place, layout)?,
 
             Constant(ref constant) => {
                 let layout = from_known_layout(layout, || {

src/librustc_mir/interpret/place.rs

@@ -624,7 +624,7 @@ where
                     // their layout on return.
                     PlaceTy {
                         place: *return_place,
-                        layout: self.layout_of_local(self.frame(), mir::RETURN_PLACE)?,
+                        layout: self.layout_of_local(self.frame(), mir::RETURN_PLACE, None)?,
                     },
                 None => return err!(InvalidNullPointerUsage),
             },
@@ -633,7 +633,7 @@ where
                     frame: self.cur_frame(),
                     local,
                 },
-                layout: self.layout_of_local(self.frame(), local)?,
+                layout: self.layout_of_local(self.frame(), local, None)?,
             },
 
             Projection(ref proj) => {
@@ -901,7 +901,7 @@ where
                         // We need the layout of the local.  We can NOT use the layout we got,
                         // that might e.g., be an inner field of a struct with `Scalar` layout,
                         // that has different alignment than the outer field.
-                        let local_layout = self.layout_of_local(&self.stack[frame], local)?;
+                        let local_layout = self.layout_of_local(&self.stack[frame], local, None)?;
                         let ptr = self.allocate(local_layout, MemoryKind::Stack);
                         // We don't have to validate as we can assume the local
                         // was already valid for its type.

src/librustc_mir/interpret/terminator.rs

@@ -309,7 +309,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                         mir.spread_arg,
                         mir.args_iter()
                             .map(|local|
-                                (local, self.layout_of_local(self.frame(), local).unwrap().ty)
+                                (local, self.layout_of_local(self.frame(), local, None).unwrap().ty)
                             )
                             .collect::<Vec<_>>()
                     );
@@ -383,7 +383,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                         }
                     } else {
                         let callee_layout =
-                            self.layout_of_local(self.frame(), mir::RETURN_PLACE)?;
+                            self.layout_of_local(self.frame(), mir::RETURN_PLACE, None)?;
                         if !callee_layout.abi.is_uninhabited() {
                             return err!(FunctionRetMismatch(
                                 self.tcx.types.never, callee_layout.ty